Mo. Rev. Stat. § 41.520

In case of insurrection, invasion, tumult, riot, breach of the peace, public calamity or catastrophe, or imminent danger thereof, or in the event any emergency in which all or any part of the organized militia is actively engaged in service upon order of the governor, the governor may suspend any and all provisions of this military code or other laws of the state which require advertisement for bids for purchase of supplies and employment of service.